Fig. 5: Ultrafast fs laser writing of skyrmions in Fe2.84±0.05GaTe2.
a Schematic of the in-situ optical LTEM experiments. The sample was exposed to a single-shot fs laser pulse with an applied out-of-plane magnetic field. The defocused Lorentz phase images (d = 2 mm) captured the magnetic state at each step before and after the fs-laser pulse excitation. The right panel shows the typical spin configurations of stripe, single domain, and Néel-type skyrmions. b Schematic of the ultrafast demagnetization process for writing skyrmions from an initial stripe domain by a fs laser pulse. The sample is temporarily laser-heated above Tc to melt the existing spin ordering, followed by quenching with external magnetic field to form a new spin ordering, skyrmions. c Illustration of single-shot laser pulse excitation from field-polarized magnetic state to subsequent laser-accessible magnetic states. The blue and red lines indicate the magnetization states during field swapping of Hall hysteresis curve. The inset shows corresponding Lorentz phase images before and after fs-laser pulses. d Simulated laser-induced stripe domain to skyrmion evolution process under an out-of-plane magnetic field of 46 mT. The magnetization along the z-axis (Mz) is represented by the color bar (+Mz in red and −Mz in blue).
